As a conventional image forming apparatus, a multi-stylus printer using needle-like electrodes is used (U.S. Pat. No. 4,396,927).
In this multi-stylus printer, an image forming electrode provided with a large number of needle-like electrodes and a cylindrical opposite electrode are oppositely disposed with a predetermined spacing (gap) in which a recording material is interposed in contact with the image forming electrode. In this state, a voltage corresponding to an image signal is applied to the image forming electrode to cause gap electric discharge, so that a toner image is formed.
In the conventional multi-stylus printer using the needle-like electrodes as the image forming electrode, a density of an image portion cannot be sufficiently obtained. Further, there arose a problem such that a so-called fog by which the toner is deposited on a non-image portion cannot be sufficiently reduced.
FIG. 29 is a schematic illustration of a conventional image forming apparatus using a needle-like electrode, wherein an opposite (counter) electrode 302 carries a toner T and is disposed opposed to an image forming electrode 301 via a recording material 303. The toner T carried on the opposite electrode 302 has a toner contact area in which it contacts the recording material 303. In this state, a voltage corresponding to an electrical signal is applied to the image forming electrode 301, so that the toner T is deposited on the recording material 303. Simultaneously, the recording material is moved in an arrow a direction at a certain speed, so that the toner image is formed on the recording material.
However, in the case where an image forming electrode toner image is formed in the constitution as described above, such a phenomenon that the toner image formed by the image forming electrode 301 is disturbed in a toner contact area downstream of a contact position of the image forming electrode 301 with respect to a movement direction of the recording material 301 occurs. For that reason, there arose problems that a toner image density is lowered and fog is increased.